Semiconductor device

ABSTRACT

A semiconductor device includes first active patterns and second active patterns on a substrate, a first source/drain region on the first active patterns, a second source/drain region on the second active patterns and a device isolation layer filling a first trench between adjacent ones of the first active patterns and a second trench between adjacent ones of the second active patterns. A liner layer is disposed on the device isolation layer between the adjacent ones of the second active patterns. The device isolation layer between the adjacent ones of the first active patterns has a recess therein under the first source/drain region and a bottom surface of the liner layer between the adjacent ones of the second active patterns is higher than the recess.

CROSS-REFERENCE TO RELATED APPLICATION

This U.S. non-provisional patent application claims priority under 35U.S.C. § 119 to Korean Patent Application No. 10-2017-0098636, filed onAug. 3, 2017, in the Korean Intellectual Property Office, the disclosureof which is hereby incorporated by reference in its entirety.

BACKGROUND

Embodiments of the inventive concepts relate to semiconductor devicesand, more particularly, to semiconductor devices including field effecttransistors.

Semiconductor devices are widely used in the electronic industry becauseof their small sizes, multi-functional characteristics, and/or lowmanufacturing costs. Semiconductor devices may be categorized as any oneof semiconductor memory devices storing logical data, semiconductorlogic devices processing logical data, and hybrid semiconductor deviceshaving both the function of the semiconductor memory devices and thefunction of the semiconductor logic devices. Semiconductor devices withexcellent characteristics have been in increasing demand with thedevelopment of the electronic industry. For example, high-reliable,high-speed, and/or multi-functional semiconductor devices have been inincreasing demand. To satisfy the demand, semiconductor devices havebeen highly integrated and structures of semiconductor devices havebecome more and more complicated.

SUMMARY

Embodiments of the inventive concepts may provide a semiconductor deviceincluding a field effect transistor with improved electricalcharacteristics.

In an aspect, a semiconductor device includes first active patterns andsecond active patterns on a substrate, a first source/drain region onthe first active patterns, a second source/drain region on the secondactive patterns and a device isolation layer filling a first trenchbetween adjacent ones of the first active patterns and a second trenchbetween adjacent ones of the second active patterns. A liner layer isdisposed on the device isolation layer between the adjacent ones of thesecond active patterns. The device isolation layer between the adjacentones of the first active patterns has a recess therein under the firstsource/drain region and a bottom surface of the liner layer between theadjacent ones of the second active patterns is higher than the recess.

In an aspect, a semiconductor device includes a substrate having a firstregion and a second region, first active patterns on the first region,second active patterns on the second region, and a device isolationlayer defining the first and second active patterns on the first andsecond regions. A residual spacer layer is disposed on the deviceisolation layer between adjacent ones of the first active patterns. Aliner layer is disposed on the device isolation layer between adjacentones of the second active patterns. A pitch between the second activepatterns is greater than a pitch between the first active patterns and abottom surface of the residual spacer layer is higher than a bottomsurface of the liner layer.

In an aspect, a semiconductor device includes an active fin on asubstrate, a device isolation layer covering a sidewall of a lowerportion of the active fin, a source/drain region on the active fin and aprotective insulating layer covering a sidewall of an upper portion ofthe active fin and the source/drain region. A thickness of theprotective insulating layer on the sidewall of the upper portion of theactive fin is greater than a thickness of the protective insulatinglayer on the source/drain region.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive concepts will become more apparent in view of the attacheddrawings and accompanying detailed description.

FIG. 1 is a plan view illustrating a semiconductor device according tosome embodiments of the inventive concepts.

FIGS. 2A to 2H are cross-sectional views taken along lines A-A′, B-B′,C-C′, D-D′, E-E′, F-F′, G-G′, and H-H′ of FIG. 1, respectively.

FIGS. 3, 6, 8, and 10 are plan views illustrating a method formanufacturing a semiconductor device according to some embodiments ofthe inventive concepts.

FIGS. 4A and 5A are cross-sectional views taken along a line A-A′ ofFIG. 3.

FIGS. 4B and 5B are cross-sectional views taken along a line B-B′ ofFIG. 3.

FIGS. 4C and 5C are cross-sectional views taken along a line C-C′ ofFIG. 3.

FIGS. 4D and 5D are cross-sectional views taken along a line D-D′ ofFIG. 3.

FIGS. 7A, 9A, and 11A are cross-sectional views taken along lines A-A′of FIGS. 6, 8, and 10, respectively.

FIGS. 7B, 9B, and 11B are cross-sectional views taken along lines B-B′of FIGS. 6, 8, and 10, respectively.

FIGS. 7C, 9C, and 11C are cross-sectional views taken along lines C-C′of FIGS. 6, 8, and 10, respectively.

FIGS. 7D, 9D, and 11D are cross-sectional views taken along lines D-D′of FIGS. 6, 8, and 10, respectively.

FIGS. 7E, 9E, and 11E are cross-sectional views taken along lines E-E′of FIGS. 6, 8, and 10, respectively.

FIGS. 7F, 9F, and 11F are cross-sectional views taken along lines F-F′of FIGS. 6, 8, and 10, respectively.

FIGS. 7G, 9G, and 11G are cross-sectional views taken along lines G-G′of FIGS. 6, 8, and 10, respectively.

FIGS. 711, 9H, and 11H are cross-sectional views taken along lines H-H′of FIGS. 6, 8, and 10, respectively.

FIG. 12 is a cross-sectional view taken along the line C-C′ of FIG. 1 toillustrate a semiconductor device according to some embodiments of theinventive concepts.

FIG. 13 is a plan view illustrating a semiconductor device according tosome embodiments of the inventive concepts.

FIGS. 14A to 14F are cross-sectional views taken along lines A-A′, B-B′,C-C′, D-D′, E-E′, and F-F′ of FIG. 13, respectively.

FIG. 15 is a plan view illustrating a method for manufacturing asemiconductor device according to some embodiments of the inventiveconcepts.

FIGS. 16A, 17A, 18A, and 19A are cross-sectional views taken along aline A-A′ of FIG. 15.

FIGS. 16B, 17B, 18B, and 19B are cross-sectional views taken along aline B-B′ of FIG. 15.

FIGS. 16C, 17C, 18C, and 19C are cross-sectional views taken along aline C-C′ of FIG. 15.

FIGS. 16D, 17D, 18D, and 19D are cross-sectional views taken along aline D-D′ of FIG. 15.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 is a plan view illustrating a semiconductor device according tosome embodiments of the inventive concepts. FIGS. 2A to 2H arecross-sectional views taken along lines A-A′, B-B′, C-C′, D-D′, E-E′,F-F′, G-G′, and H-H′ of FIG. 1, respectively.

A substrate 100 having a first region RG1 and a second region RG2 may beprovided. First, the first region RG1 of the substrate 100 will bedescribed hereinafter in detail with reference to FIGS. 1 and 2A to 2C.The first region RG1 of the substrate 100 may include a PMOSFET regionPR and an NMOSFET region NR. The substrate 100 may be a semiconductorsubstrate including silicon, germanium, or silicon-germanium or may be acompound semiconductor substrate. For example, the substrate 100 may bea silicon substrate. The first region RG1 may be a logic cell region onwhich logic transistors constituting a logic circuit of a semiconductordevice are disposed. For example, logic transistors constituting aprocessor core may be disposed on the first region RG1 (i.e., the logiccell region) of the substrate 100. Some of the logic transistors may bedisposed on the first region RG1.

A device isolation layer ST may be provided in an upper portion of thesubstrate 100. The device isolation layer ST may include an insulatingmaterial such as a silicon oxide layer. The PMOSFET region PR and theNMOSFET region NR may be spaced apart from each other in a firstdirection D1 with the device isolation layer ST interposed therebetween.The first direction D1 may be parallel to a top surface of the substrate100. The PMOSFET region PR and the NMOSFET region NR may extend in asecond direction D2 intersecting the first direction D1. The deviceisolation layer ST between the PMOSFET region PR and the NMOSFET regionNR may be deeper than the device isolation layer ST between activepatterns AP1 or AP2.

A plurality of the active patterns AP1 and AP2 extending in the seconddirection D2 may be provided on the PMOSFET region PR and the NMOSFETregion NR. The active patterns AP1 and AP2 may include first activepatterns AP1 on the PMOSFET region PR and second active patterns AP2 onthe NMOSFET region NR. The first and second active patterns AP1 and AP2may be portions of the substrate 100, which may protrude from a surfaceof the substrate 100. The first and second active patterns AP1 and AP2may be arranged in the first direction D1.

First trenches TR1 may be defined between the first active patterns AP1adjacent to each other and between the second active patterns AP2adjacent to each other. A second trench TR2 may be defined between thePMOSFET region PR and the NMOSFET region NR adjacent to each other. Thedevice isolation layer ST may fill the first and second trenches TR1 andTR2.

The device isolation layer ST filling the first trenches TR1 may definethe first and second active patterns AP1 and AP2. The device isolationlayer ST may directly cover sidewalls of lower portions of the first andsecond active patterns AP1 and AP2. In FIGS. 1, 2B, and 2C, three firstactive patterns AP1 are illustrated on the PMOSFET region PR and threesecond active patterns AP2 are illustrated on the NMOSFET region NR.However, embodiments of the inventive concepts are not limited thereto.

Upper portions of the first and second active patterns AP1 and AP2 maybe higher than a top surface of the device isolation layer ST. The upperportions of the first and second active patterns AP1 and AP2 mayvertically protrude from the device isolation layer ST. The upperportions of the first and second active patterns AP1 and AP2 may havefin-shapes protruding from the device isolation layer ST.

The upper portions of the first active patterns AP1 may include firstchannel regions CH1 and first source/drain regions SD1. The firstsource/drain regions SD1 may be P-type dopant regions. Each of the firstchannel regions CH1 may be disposed between a pair of the firstsource/drain regions SD1 adjacent to each other. In some embodiments,three first active patterns AP1 adjacent to each other in the firstdirection D1 may share one first source/drain region SD1.

The upper portions of the second active patterns AP2 may include secondchannel regions CH2 and second source/drain regions SD2. The secondsource/drain regions SD2 may be N-type dopant regions. Each of thesecond channel regions CH2 may be disposed between a pair of the secondsource/drain regions SD2 adjacent to each other. In some embodiments,three second active patterns AP2 adjacent to each other in the firstdirection D1 may share one second source/drain region SD2.

The first and second source/drain regions SD1 and SD2 may includeepitaxial patterns formed by a selective epitaxial growth (SEG) process.Top surfaces of the first and second source/drain regions SD1 and SD2may be disposed at a higher level than top surfaces of the first andsecond channel regions CH1 and CH2. In some embodiments, the epitaxialpatterns adjacent to each other in the first direction D1 on the PMOSFETregion PR may be connected to each other to constitute one firstsource/drain region SD1 on the first active patterns AP1. The epitaxialpatterns adjacent to each other in the first direction D1 on the NMOSFETregion NR may be connected to each other to constitute one secondsource/drain region SD2 on the second active patterns AP2.

The first source/drain regions SD1 may include a semiconductor elementof which a lattice constant is greater than that of the semiconductorelement of the substrate 100. Thus, the first source/drain regions SD1may provide compressive stress to the first channel regions CH1. Forexample, the first source/drain regions SD1 may includesilicon-germanium (SiGe). The second source/drain regions SD2 mayinclude a semiconductor element of which a lattice constant is equal toor smaller than that of the semiconductor element of the substrate 100.For example, the second source/drain regions SD2 may include the samesemiconductor element (e.g., silicon) as the substrate 100.

Residual spacer layers RSL may be provided between the firstsource/drain region SD1 and the device isolation layer ST and betweenthe second source/drain region SD2 and the device isolation layer ST.Each of the residual spacer layers RSL may cover the top surface of thedevice isolation layer ST. The residual spacer layers RSL may includethe same material as gate spacers GS.

A first air gap AG1 may be defined between the first source/drain regionSD1 and the residual spacer layer RSL. The residual spacer layer RSL maydefine a bottom of the first air gap AG1. A second air gap AG2 may bedefined between the second source/drain region SD2 and the residualspacer layer RSL. The residual spacer layer RSL may define a bottom ofthe second air gap AG2.

Gate electrodes GE extending in the first direction D1 may be providedon the first and second active patterns AP1 and AP2 to intersect thefirst and second active patterns AP1 and AP2. The gate electrodes GE maybe spaced apart from each other in the second direction D2. The gateelectrodes GE may vertically overlap with the first and second channelregions CH1 and CH2. Each of the gate electrodes GE may surround a topsurface and both sidewalls of each of the first and second channelregions CH1 and CH2 (see FIG. 2B). For example, the gate electrodes GEmay include at least one of a conductive metal nitride (e.g., titaniumnitride or tantalum nitride) or a metal material (e.g., titanium,tantalum, tungsten, copper, or aluminum).

A pair of gate spacers GS may be disposed on both sidewalls of each ofthe gate electrodes GE, respectively. The gate spacers GS may extendalong the gate electrodes GE in the first direction D1. Top surfaces ofthe gate spacers GS may be higher than top surfaces of the gateelectrodes GE. The top surfaces of the gate spacers GS may be coplanarwith a top surface of a first interlayer insulating layer 140 to bedescribed later. The gate spacers GS may include at least one of SiCN,SiCON, or SiN. In certain embodiments, each of the gate spacers GS mayhave a multi-layered structure formed of at least two of SiCN, SiCON, orSiN.

Gate dielectric patterns GI may be disposed between the gate electrodesGE and the active patterns AP1 and AP2. Each of the gate dielectricpatterns GI may extend along a bottom surface of each of the gateelectrodes GE. Each of the gate dielectric patterns GI may cover the topsurface and the both sidewalls of each of the first and second channelregions CH1 and CH2. The gate dielectric patterns GI may include ahigh-k dielectric material. For example, the high-k dielectric materialmay include at least one of hafnium oxide, hafnium-silicon oxide,lanthanum oxide, zirconium oxide, zirconium-silicon oxide, tantalumoxide, titanium oxide, barium-strontium-titanium oxide, barium-titaniumoxide, strontium-titanium oxide, lithium oxide, aluminum oxide,lead-scandium-tantalum oxide, or lead-zinc niobate.

A gate capping pattern GP may be provided on each of the gate electrodesGE. The gate capping patterns GP may extend along the gate electrodes GEin the first direction D1. The gate capping patterns GP may include amaterial having an etch selectivity with respect to first and secondinterlayer insulating layers 140 and 150 to be described later. Forexample, the gate capping patterns GP may include at least one of SiON,SiCN, SiCON, or SiN.

A first interlayer insulating layer 140 may be provided on the substrate100. The first interlayer insulating layer 140 may cover the gatespacers GS and the first and second source/drain regions SD1 and SD2. Atop surface of the first interlayer insulating layer 140 may besubstantially coplanar with top surfaces of the gate capping patterns GPand the top surfaces of the gate spacers GS.

An etch stop layer ESL may be disposed between the first interlayerinsulating layer 140 and the gate spacers GS, between the firstinterlayer insulating layer 140 and the source/drain regions SD1 andSD2, and between the first interlayer insulating layer 140 and thedevice isolation layer ST. For example, the etch stop layer ESL mayinclude a silicon nitride layer. A second interlayer insulating layer150 may be disposed on the first interlayer insulating layer 140 and thegate capping patterns GP. For example, each of the first and secondinterlayer insulating layers 140 and 150 may include a silicon oxidelayer.

The top surface of the device isolation layer ST between the firstchannel regions CH1 and the second channel regions CH2 spaced apart fromeach other in the first direction D1 may be higher than the top surfaceof the device isolation layer ST between the first source/drain regionSD1 and the second source/drain region SD2 spaced apart from each otherin the first direction D1 (see FIGS. 2B and 2C). In other words, the topsurface of the device isolation layer ST under the gate electrode GE maybe higher than the top surface of the device isolation layer ST underthe first interlayer insulating layer 140.

At least one contact AC may penetrate the second and first interlayerinsulating layers 150 and 140 between a pair of the gate electrodes GEso as to be electrically connected to the first and/or secondsource/drain regions SD1 and/or SD2. For example, the contact AC mayinclude at least one selected from metal materials such as aluminum,copper, tungsten, molybdenum, and cobalt.

Even though not shown in the drawings, a barrier layer may be disposedbetween the contact(s) AC and the source/drain regions SD1 and SD2. Thebarrier layer may include a metal layer and/or a metal nitride layer.The metal layer may include at least one of titanium, tantalum,tungsten, nickel, cobalt, or platinum. The metal nitride layer mayinclude at least one of a titanium nitride layer, a tantalum nitridelayer, a tungsten nitride layer, a nickel nitride layer, a cobaltnitride layer, or a platinum nitride layer.

Hereinafter, the second region RG2 of the substrate 100 will bedescribed in detail with reference to FIGS. 1 and 2D to 2H. Hereinafter,the descriptions to the same technical features as mentioned withreference to FIGS. 1 and 2A to 2C will be omitted or mentioned brieflyfor the purpose of ease and convenience in explanation.

The second region RG2 of the substrate 100 may include a PMOSFET regionPR and an NMOSFET region NR. The second region RG2 may be a peripheralcircuit region of the semiconductor device. In some embodiments, thesecond region RG2 may be a peripheral circuit region on whichhigh-voltage transistors constituting an input/output (I/O) terminal aredisposed.

First active patterns AP1 may be provided on the PMOSFET region PR, andsecond active patterns AP2 may be provided on the NMOSFET region NR. Adistance (or a pitch), in the first direction D1, between the firstactive patterns AP1 of the second region RG2 may be greater than adistance (or a pitch), in the first direction D1, between the firstactive patterns AP1 of the first region RG1. A distance (or a pitch), inthe first direction D1, between the second active patterns AP2 of thesecond region RG2 may be greater than a distance (or a pitch), in thefirst direction D1, between the second active patterns AP2 of the firstregion RG1. A width of each of the first and second active patterns AP1and AP2 of the second region RG2 may be substantially equal to a widthof each of the first and second active patterns AP1 and AP2 of the firstregion RG1.

Upper portions of the first active patterns AP1 may include firstchannel regions CH1 and first source/drain regions SD1. Upper portionsof the second active patterns AP2 may include second channel regions CH2and second source/drain regions SD2. In some embodiments, the firstsource/drain regions SD1 of the first active patterns AP1 adjacent toeach other in the first direction D1 may constitute one pattern (i.e.,one first source/drain region SD1) in which three epitaxial patternsadjacent to each other in the first direction D1 are merged with eachother. The second source/drain regions SD2 of the second active patternsAP2 adjacent to each other in the first direction D1 may constitute onepattern (i.e., one second source/drain region SD2) in which threeepitaxial patterns adjacent to each other in the first direction D1 aremerged with each other.

A size of the first source/drain region SD1 of the second region RG2 maybe greater than a size of the first source/drain region SD1 of the firstregion RG1, and a size of the second source/drain region SD2 of thesecond region RG2 may be greater than a size of the second source/drainregion SD2 of the first region RG1.

On the second region RG2, a first air gap AG1 under the firstsource/drain region SD1 may be greater than a second air gap AG2 underthe second source/drain region SD2. A device isolation layer ST underthe first air gap AG1 may have a recessed top surface RS. In otherwords, the device isolation layer ST under the first air gap AG1 may berecessed toward a bottom surface of the substrate 100. The recessed topsurface RS of the device isolation layer ST under the first air gap AG1may be lower than a top surface of a device isolation layer ST under thesecond air gap AG2. In some embodiments, unlike the first region RG1,the residual spacer layer RSL may not exist in the first and second airgaps AG1 and AG2 of the second region RG2.

A protective insulating layer PIN may be provided on the NMOSFET regionNR of the second region RG2. The protective insulating layer PIN mayinclude a second liner layer LIN2 and an etch stop layer ESL. The secondliner layer LIN2 may cover the top surface of the device isolation layerST on the NMOSFET region NR of the second region RG2. The second linerlayer LIN2 may also cover sidewalls of upper portions of the secondactive patterns AP2 under the second source/drain region SD2. The secondliner layer LIN2 may define a bottom of the second air gap AG2 of thesecond region RG2. The second liner layer LIN2 may not exist between thesecond channel regions CH2 and the gate electrodes GE. A bottom surfaceof the second liner layer LIN2 may be higher than the recessed topsurface RS of the device isolation layer ST under the first air gap AG1.

The second liner layer LIN2 may prevent the second active patterns AP2from leaning. In more detail, the second liner layer LIN2 may reduce orminimize stress applied to the second active patterns AP2. For example,the second liner layer LIN2 may include the same material (e.g., asilicon nitride layer) as the etch stop layer ESL. The silicon nitridelayer may provide tensile stress to the second active patterns AP2, andthus electrical characteristics of an N-channel MOS field effecttransistor (NMOSFET) may be improved. In addition, the silicon nitridelayer may protect the second source/drain region SD2.

The protective insulating layer PIN may cover the sidewalls of the upperportions of the second active patterns AP2 and the second source/drainregion SD2. A thickness T1 of the protective insulating layer PIN on thesidewall of the upper portion of at least one of the second activepatterns AP2 may be greater than a thickness T2 of the protectiveinsulating layer PIN on the second source/drain region SD2. This may bebecause the protective insulating layer PIN on the sidewall of the upperportion of at least one of the second active patterns AP2 includes thesecond liner layer LIN2 and the etch stop layer ESL but the protectiveinsulating layer PIN on the second source/drain region SD2 includes onlythe etch stop layer ESL.

A width of each of the gate electrodes GE of the second region RG2 maybe greater than a width of each of the gate electrodes GE of the firstregion RG1. The recessed top surface RS of the device isolation layer STon the PMOSFET region PR of the second region RG2 may be lower than abottom surface of the gate electrode GE adjacent thereto. Insulatingpatterns AO may be disposed between the second liner layer LIN2 and thegate electrodes GE on the NMOSFET region NR of the second region RG2.The second air gap AG2 of the second region RG2 may be surrounded by thegate spacers GS adjacent to each other, the insulating patterns AOadjacent to each other, the second source/drain region SD2, and thesecond liner layer LIN2 (see FIGS. 2E and 2H). For example, theinsulating patterns AO may include the same material (e.g., a siliconoxide layer) as the device isolation layer ST.

FIGS. 3, 6, 8, and 10 are plan views illustrating a method formanufacturing a semiconductor device according to some embodiments ofthe inventive concepts. FIGS. 4A and 5A are cross-sectional views takenalong a line A-A′ of FIG. 3. FIGS. 4B and 5B are cross-sectional viewstaken along a line B-B′ of FIG. 3. FIGS. 4C and 5C are cross-sectionalviews taken along a line C-C′ of FIG. 3. FIGS. 4D and 5D arecross-sectional views taken along a line D-D′ of FIG. 3. FIGS. 7A, 9A,and 11A are cross-sectional views taken along lines A-A′ of FIGS. 6, 8,and 10, respectively. FIGS. 7B, 9B, and 11B are cross-sectional viewstaken along lines B-B′ of FIGS. 6, 8, and 10, respectively. FIGS. 7C,9C, and 11C are cross-sectional views taken along lines C-C′ of FIGS. 6,8, and 10, respectively. FIGS. 7D, 9D, and 11D are cross-sectional viewstaken along lines D-D′ of FIGS. 6, 8, and 10, respectively. FIGS. 7E,9E, and 11E are cross-sectional views taken along lines E-E′ of FIGS. 6,8, and 10, respectively. FIGS. 7F, 9F, and 11F are cross-sectional viewstaken along lines F-F′ of FIGS. 6, 8, and 10, respectively. FIGS. 7G,9G, and 11G are cross-sectional views taken along lines G-G′ of FIGS. 6,8, and 10, respectively. FIGS. 7H, 9H, and 11H are cross-sectional viewstaken along lines H-H′ of FIGS. 6, 8, and 10, respectively.

Referring to FIGS. 3 and 4A to 4D, a substrate 100 having a first regionRG1 and a second region RG2 may be provided. The first region RG1 may bea logic cell region and the second region RG2 may be a peripheralcircuit region. The substrate 100 may be patterned to form activepatterns AP1 and AP2. In more detail, the formation of the activepatterns AP1 and AP2 may include forming mask patterns on the substrate100, and anisotropically etching the substrate 100 using the maskpatterns as etch masks. First trenches TR1 may be formed between theactive patterns AP1 and AP2.

A distance (i.e., a pitch), in a first direction D1, between the activepatterns AP1 and AP2 on the first region RG1 may be a first distance P1.A distance (i.e., a pitch), in the first direction D1, between theactive patterns AP1 and AP2 on the second region RG2 may be a seconddistance P2. The patterning process may be performed such that thesecond distance P2 is greater than the first distance P1. In someembodiments, a width of each of the active patterns AP1 and AP2 on thefirst region RG1 may be substantially equal to a width of each of theactive patterns AP1 and AP2 on the second region RG2.

The active patterns AP1 and AP2 on a PMOSFET region PR and an NMOSFETregion NR of the first region RG1 may remain, but the active patternsAP1 and AP2 on the other region of the first region RG1 may be removed.In more detail, a mask pattern may be formed to cover the PMOSFET regionPR and the NMOSFET region NR of the first region RG1, and an etchingprocess may be performed using the mask pattern as an etch mask. Thus,first active patterns AP1 may remain on the PMOSFET region PR, andsecond active patterns AP2 may remain on the NMOSFET region NR. Theactive patterns AP1 and AP2 on a PMOSFET region PR and an NMOSFET regionNR of the second region RG2 may also remain, but the active patterns AP1and AP2 on the other region of the second region RG2 may also beremoved.

A second trench TR2 deeper than the first trenches TR1 may be formedbetween the PMOSFET region PR and the NMOSFET region NR of the firstregion RG1. In detail, the second trench TR2 may be formed by etching anupper portion of the substrate 100 between the PMOSFET region PR and theNMOSFET region NR of the first region RG1.

A device isolation layer ST may be formed to fill the first and secondtrenches TR1 and TR2 of the first and second regions RG1 and RG2 of thesubstrate 100. In more detail, an insulating layer (e.g., a siliconoxide layer) may be formed to completely fill the first and secondtrenches TR1 and TR2. The insulating layer may completely cover thefirst and second active patterns AP1 and AP2. The insulating layer maybe recessed until upper portions of the first and second active patternsAP1 and AP2 are exposed.

The insulating layer on the first region RG1 may be recessed (or etched)such that a top surface of the device isolation layer ST of the firstregion RG1 may be disposed at a first level LV1. The insulating layer onthe second region RG2 may be recessed (or etched) such that a topsurface of the device isolation layer ST of the second region RG2 may bedisposed at a second level LV2. The second level LV2 may be lower thanthe first level LV1. Since the second distance P2 between the activepatterns AP1 and AP2 on the second region RG2 is greater than the firstdistance P1 between the active patterns AP1 and AP2 on the first regionRG1, the insulating layer on the second region RG2 may be etched morethan the insulating layer on the first region RG1. In other words, anetching amount of the insulating layer on the second region RG2 may begreater than that of the insulating layer on the first region RG1.

A first liner layer LIN1 may be formed to cover the exposed upperportions of the first active patterns AP1 on the first and secondregions RG1 and RG2. A second liner layer LIN2 may be formed to coverthe exposed upper portions of the second active patterns AP2 on thefirst and second regions RG1 and RG2. The first and second liner layersLIN1 and LIN2 may be formed of at least one of a silicon nitride layer,a poly-silicon layer, or a silicon oxide layer. The first and secondliner layers LIN1 and LIN2 may include the same material or may includedifferent materials from each other. In the present embodiment, thefirst liner layer LIN1 may include the poly-silicon layer, and thesecond liner layer LIN2 may include the silicon nitride layer.

The first liner layer LIN1 and the second liner layer LIN2 may beselectively formed on the first active patterns AP1 and the secondactive patterns AP2, respectively. For example, the first liner layerLIN1 may be formed on the first active patterns AP1 by using a maskselectively opening the PMOSFET regions PR, and the second liner layerLIN2 may be formed on the second active patterns AP2 by using a maskselectively opening the NMOSFET regions NR.

The first and second liner layers LIN1 and LIN2 may prevent the firstand second active patterns AP1 and AP2 from leaning. In more detail, thefirst and second liner layers LIN1 and LIN2 may reduce or minimizestress applied to the first and second active patterns AP1 and AP2.

Referring to FIGS. 3 and 5A to 5D, insulating patterns AO may be formedon the first and second liner layers LIN1 and LIN2 of the second regionRG2. In more detail, an additional insulating layer may be formed on anentire top surface of the substrate 100 to completely cover the firstand second active patterns AP1 and AP2. The additional insulating layermay be etched until upper portions of the first and second activepatterns AP1 and AP2 are exposed. The additional insulating layer on thesecond region RG2 may be etched to form the insulating patterns AO.

In some embodiments, the etching process may be performed until thefirst and second liner layers LIN1 and LIN2 on the first region RG1 areremoved. In certain embodiments, the etching process may be finishedbefore the first and second liner layers LIN1 and LIN2 on the firstregion RG1 are completely removed. Thus, the first and second linerlayers LIN1 and LIN2 may also remain on the first region RG1 even thoughnot shown in the drawings.

Since the top surface of the device isolation layer ST on the secondregion RG2 is lower than the top surface of the device isolation layerST on the first region RG1, portions of the first and second linerlayers LIN1 and LIN2 may remain on the second region RG2 after theetching process. The insulating patterns AO on the first and secondliner layers LIN1 and LIN2 may also remain. The first and second linerlayers LIN1 and LIN2 remaining on the second region RG2 may cover atleast portions of sidewalls of the first and second active patterns AP1and AP2 of the second region RG2.

Referring to FIGS. 6 and 7A to 7H, a thermal treatment process may beperformed on the substrate 100. Since the first liner layer LIN1 isformed of the poly-silicon layer in the present embodiment, the firstliner layer LIN1 may be oxidized during the thermal treatment process.Thus, a silicon oxide layer may be formed from the first liner layerLIN1 on the second region RG2. The oxidized first liner layer LIN1 andthe insulating patterns AO may constitute (or be included in) the deviceisolation layer ST (see FIGS. 7G and 7H). On the contrary, the secondliner layer LIN2 on the second region RG2 may remain after the thermaltreatment process.

Sacrificial patterns PP may be formed to intersect the first and secondactive patterns AP1 and AP2. The sacrificial patterns PP may have lineshapes or bar shapes extending in the first direction D1. In moredetail, the formation of the sacrificial patterns PP may include forminga sacrificial layer on an entire top surface of the substrate 100,forming hard mask patterns MP on the sacrificial layer, and patterningthe sacrificial layer using the hard mask patterns MP as etch masks. Thesacrificial layer may include a poly-silicon layer. A width of each ofthe sacrificial patterns PP on the second region RG2 may be greater thana width of each of the sacrificial patterns PP on the first region RG1.

A pair of gate spacers GS may be formed on both sidewalls of each of thesacrificial patterns PP, respectively. The formation of the gate spacersGS may include conformally forming a spacer layer on an entire topsurface of the substrate 100 and anisotropically etching the spacerlayer. For example, the spacer layer may include at least one of SiCN,SiCON, or SiN. For another example, the spacer layer may be formed of amulti-layer including at least two of SiCN, SiCON, or SiN.

The spacer layer on the active patterns AP1 and AP2 at both sides ofeach of the sacrificial patterns PP may be etched by the anisotropicetching process, and thus residual spacer layers RSL may be formed. Theresidual spacer layers RSL may be formed simultaneously with the gatespacers GS and may include the same material as the gate spacers GS.Since the second distance P2 between the active patterns AP1 and AP2 onthe second region RG2 is greater than the first distance P1 between theactive patterns AP1 and AP2 on the first region RG1, the etching of theresidual spacer layers RSL on the second region RG2 may be more than theetching of the residual spacer layers RSL on the first region RG1. Thus,a thickness of the residual spacer layer RSL on the second region RG2may be less than a thickness of the residual spacer layer RSL on thefirst region RG1.

Referring to FIGS. 8 and 9A to 9H, first source/drain regions SD1 may beformed at both sides of each of the sacrificial patterns PP on thePMOSFET regions PR, and second source/drain regions SD2 may be formed atboth sides of each of the sacrificial patterns PP on the NMOSFET regionsNR.

In more detail, upper portions of the first and second active patternsAP1 and AP2 may be etched using the hard mask patterns MP and the gatespacers GS as etch masks to form recess regions RSG. Since the residualspacer layers RSL on the first region RG1 are relatively thick, portionsthereof may remain after the etching process. The residual spacer layersRSL on the first region RG1 may protect the device isolation layer STdisposed thereunder during the etching process.

Since the residual spacer layers RSL on the second region GR2 arerelatively thin, the residual spacer layers RSL on the second region RG2may be completely removed during the etching process. Since the residualspacer layers RSL are completely removed, the device isolation layer STon the PMOSFET region PR of the second region RG2 may be over-etchedduring the etching process. Thus, the device isolation layer ST on thePMOSFET region PR of the second region RG2 may have a recessed topsurface RS. The second liner layer LIN2 on the NMOSFET region NR of thesecond region RG2 may protect the device isolation layer ST disposedthereunder during the etching process. Thus, the top surface of thedevice isolation layer ST on the NMOSFET region NR of the second regionRG2 may be disposed at a higher level than the recessed top surface RSof the device isolation layer ST on the PMOSFET region PR of the secondregion RG2.

First source/drain regions SD1 may be formed by performing a selectiveepitaxial growth (SEG) process using inner surfaces of the recessregions RSG of the first active patterns AP1 as seed layers. Since thefirst source/drain regions SD1 are formed, a first channel region CH1may be defined between a pair of the first source/drain regions SD1. Forexample, the SEG process may include a chemical vapor deposition (CVD)process or a molecular beam epitaxy (MBE) process. The firstsource/drain regions SD1 may include a semiconductor element of which alattice constant is greater than that of a semiconductor element of thesubstrate 100. For example, the first source/drain regions SD1 mayinclude silicon-germanium (SiGe).

Second source/drain regions SD2 may be formed by performing a SEGprocess using inner surfaces of the recess regions RSG of the secondactive patterns AP2 as seed layers. Since the second source/drainregions SD2 are formed, a second channel region CH2 may be definedbetween a pair of the second source/drain regions SD2. For example, thesecond source/drain regions SD2 may include silicon.

The first source/drain regions SD1 and the second source/drain regionsSD2 may be sequentially formed by different processes from each other.In other words, the first source/drain regions SD1 may not be formedsimultaneously with the second source/drain regions SD2.

In the present embodiment, epitaxial patterns may be merged with eachother during the SEG process, and thus one first source/drain region SD1may be formed on the first active patterns AP1 adjacent to each other inthe first direction D1. Thus, a first air gap AG1 may be formed betweenthe first source/drain region SD1 and the device isolation layer ST. Inthe present embodiment, epitaxial patterns may be merged with each otherduring the SEG process, and thus one second source/drain region SD2 maybe formed on the second active patterns AP2 adjacent to each other inthe first direction D1. Thus, a second air gap AG2 may be formed betweenthe second source/drain region SD2 and the device isolation layer ST.

Referring to FIGS. 10 and 11A to 11H, an etch stop layer ESL may beconformally formed on an entire top surface of the substrate 100. Theetch stop layer ESL may directly cover the first and second source/drainregions SD1 and SD2. The etch stop layer ESL may include a siliconnitride layer. On the NMOSFET region NR of the second region RG2, theetch stop layer ESL and the second liner layer LIN2 may constitute aprotective insulating layer PIN.

A first interlayer insulating layer 140 may be formed to cover the firstand second source/drain regions SD1 and SD2, the hard mask patterns MP,and the gate spacers GS. For example, the first interlayer insulatinglayer 140 may include a silicon oxide layer.

The first interlayer insulating layer 140 may be planarized until topsurfaces of the sacrificial patterns PP are exposed. The planarizationprocess of the first interlayer insulating layer 140 may be performedusing an etch-back process or a chemical mechanical polishing (CMP)process. The hard mask patterns MP may be completely removed during theplanarization process. As a result, a top surface of the firstinterlayer insulating layer 140 may be substantially coplanar with thetop surfaces of the sacrificial patterns PP and top surfaces of the gatespacers GS.

The sacrificial patterns PP may be replaced with gate electrodes GE,respectively. In more detail, the exposed sacrificial patterns PP may beselectively removed. The removal of the sacrificial patterns PP may beperformed using a wet etching process selectively etching silicon.During the wet etching process, an etching solution may be provided tothe first source/drain region SD1 through the first air gap AG1 on thePMOSFET region PR of the second region RG2. However, since the firstsource/drain region SD1 is formed of silicon-germanium (SiGe), the firstsource/drain region SD1 may not be etched even though the etchingsolution is provided to the first source/drain region SD1. On the otherhand, since the second source/drain region SD2 is formed of silicon, thesecond source/drain region SD2 may be etched if the etching solution isprovided to the second source/drain region SD2. However, according tosome embodiments of the inventive concepts, the second liner layer LIN2may remain under the sacrificial patterns PP to prevent the etchingsolution from being provided into the second air gap AG2 of the secondregion RG2. On the first region RG1, the residual spacer layers RSL mayexist between the sacrificial patterns PP and the second source/drainregions SD2 to prevent the second source/drain regions SD2 from beingetched during the wet etching process.

A gate dielectric pattern GI, a gate electrode GE, and a gate cappingpattern GP may be formed in each of empty spaces formed by the removalof the sacrificial patterns PP. The gate dielectric pattern GI may beconformally formed in the empty space and may not completely fill theempty space. The gate dielectric pattern GI may be formed using anatomic layer deposition (ALD) process or a chemical oxidation process.The gate dielectric pattern GI may include a high-k dielectric material.For example, the high-k dielectric material may include at least one ofhafnium oxide, hafnium-silicon oxide, lanthanum oxide, zirconium oxide,zirconium-silicon oxide, tantalum oxide, titanium oxide,barium-strontium-titanium oxide, barium-titanium oxide,strontium-titanium oxide, lithium oxide, aluminum oxide,lead-scandium-tantalum oxide, or lead-zinc niobate.

A gate electrode layer may be formed to completely fill the empty space,and a planarization process may be performed on the gate electrode layerto form the gate electrode GE. For example, the gate electrode layer mayinclude at least one of a conductive metal nitride (e.g., titaniumnitride or tantalum nitride) or a metal material (e.g., titanium,tantalum, tungsten, copper, or aluminum).

Subsequently, upper portions of the gate electrodes GE may be recessed.The gate capping patterns GP may be formed on the recessed gateelectrodes GE, respectively. The gate capping patterns GP may completelyfill the recessed regions on the gate electrodes GE, respectively. Forexample, the gate capping patterns GP may include at least one of SiON,SiCN, SiCON, or SiN.

Referring again to FIGS. 1 and 2A to 2H, a second interlayer insulatinglayer 150 may be formed on the first interlayer insulating layer 140 andthe gate capping patterns GP. The second interlayer insulating layer 150may include a silicon oxide layer or a low-k oxide layer. For example,the low-k oxide layer may include a silicon oxide layer doped withcarbon, e.g., SiCOH. The second interlayer insulating layer 150 may beformed by a CVD process.

Contacts AC may be formed to penetrate the second interlayer insulatinglayer 150 and the first interlayer insulating layer 140. The contacts ACmay be connected to the first and second source/drain regions SD1 andSD2. In more detail, the formation of the contacts AC may includeforming contact holes penetrating the second interlayer insulating layer150 and the first interlayer insulating layer 140, and forming aconductive layer filling the contact holes. For example, the conductivelayer may include at least one of aluminum, copper, tungsten,molybdenum, or cobalt.

Subsequently, even though not shown in the drawings, an additionalinterlayer insulating layer and metal interconnection lines may beformed on the second interlayer insulating layer 150.

FIG. 12 is a cross-sectional view taken along the line C-C′ of FIG. 1 toillustrate a semiconductor device according to some embodiments of theinventive concepts. In the present embodiment, the descriptions to thesame technical features as in the embodiment of FIGS. 1 and 2A to 2Hwill be omitted for the purpose of ease and convenience in explanation.In other words, differences between the present embodiment and theembodiment of FIGS. 1 and 2A to 2H will be mainly described hereinafter.

Referring to FIGS. 1, 2H, and 12, the second liner layer LIN2 may beprovided on the NMOSFET region NR of the first region RG1 as well as theNMOSFET region NR of the second region RG2. The second liner layer LIN2of the NMOSFET region NR of the first region RG1 may be disposed betweenthe device isolation layer ST and the residual spacer layer RSL. Thesecond liner layer LIN2 and the etch stop layer ESL on the NMOSFETregion NR of the first region RG1 may constitute a protective insulatinglayer PIN of the first region RG1. A level of a bottom surface of thesecond liner layer LIN2 on the NMOSFET region NR of the first region RG1may be higher than a level of a bottom surface of the second liner layerLIN2 on the NMOSFET region NR of the second region RG2.

FIG. 13 is a plan view illustrating a semiconductor device according tosome embodiments of the inventive concepts. FIGS. 14A to 14F arecross-sectional views taken along lines A-A′, B-B′, C-C′, D-D′, E-E′,and F-F′ of FIG. 13, respectively. In the present embodiment, thedescriptions to the same technical features as in the embodiment ofFIGS. 1 and 2A to 2H will be omitted for the purpose of ease andconvenience in explanation. In other words, differences between thepresent embodiment and the embodiment of FIGS. 1 and 2A to 2H will bemainly described hereinafter.

Referring to FIGS. 13 and 14A to 14F, a substrate 100 having a thirdregion RG3 and a fourth region RG4 may be provided. The third region RG3and the fourth region RG4 may be a logic cell region on which logictransistors for constituting a logic circuit are disposed, or aperipheral circuit region on which high-voltage transistors forconstituting an I/O terminal are disposed.

A plurality of active patterns AP extending in a second direction D2 maybe provided on the third region RG3 and the fourth region RG4. Widths ofthe active patterns AP on the third region RG3 may be substantiallyequal to widths of the active patterns AP on the fourth region RG4. Adistance (or a pitch) between the active patterns AP adjacent to eachother on the third region RG3 may be substantially equal to a distance(or a pitch) between the active patterns AP adjacent to each other onthe fourth region RG4.

A first trench TR1 may be defined between the active patterns APadjacent to each other on the third region RG3. A second trench TR2 maybe defined between the active patterns AP adjacent to each other on thefourth region RG4. The second trench TR2 may be deeper than the firsttrench TR1. In other words, heights (i.e., vertical lengths) of theactive patterns AP on the third region RG3 may be smaller than those ofthe active patterns AP on the fourth region RG4.

Each of the active patterns AP on the fourth region RG4 may include afirst portion PA1 and a second portion PA2 on the first portion PA1. Thefirst portion PA1 may correspond to a lower portion of the activepattern AP, and the second portion PA2 may correspond to an upperportion of the active pattern AP. A width of the active pattern AP in afirst direction D1 may decrease as a distance from a bottom surface ofthe substrate 100 increases. The width of the active pattern AP maysharply (discontinuously) decrease at a boundary between the firstportion PA1 and the second portion PA2. In other words, a sidewall ofthe active pattern AP may have a stepped profile at the boundary betweenthe first portion PA1 and the second portion PA2.

Liner layers LIN may be provided on both sidewalls of the second portionPA2 of the active pattern AP on the fourth region RG4. An outer sidewallof the liner layer LIN may be aligned with a sidewall of the firstportion PA1 of the active pattern AP. For example, the liner layer LINmay include at least one of a silicon nitride layer, a silicon oxidelayer, or a poly-silicon layer. In certain embodiments, the liner layerLIN may have a multi-layered structure formed of at least two of thesilicon nitride layer, the silicon oxide layer, or the poly-siliconlayer. On the other hand, a liner layer may not exist on the thirdregion RG3.

In the present embodiment, all of transistors on the third region RG3and the fourth region RG4 may be P-channel MOS field effect transistors(PMOSFETs) or N-channel MOS field effect transistors (NMOSFETs).Alternatively, a conductivity type of the transistors of the thirdregion RG3 may be different from that of the transistors of the fourthregion RG4. However, embodiments of the inventive concepts are notlimited thereto.

FIG. 15 is a plan view illustrating a method for manufacturing asemiconductor device according to some embodiments of the inventiveconcepts. FIGS. 16A, 17A, 18A, and 19A are cross-sectional views takenalong a line A-A′ of FIG. 15. FIGS. 16B, 17B, 18B, and 19B arecross-sectional views taken along a line B-B′ of FIG. 15. FIGS. 16C,17C, 18C, and 19C are cross-sectional views taken along a line C-C′ ofFIG. 15. FIGS. 16D, 17D, 18D, and 19D are cross-sectional views takenalong a line D-D′ of FIG. 15. In the present embodiment, thedescriptions to the same technical features as in the embodiment ofFIGS. 3 to 11H will be omitted for the purpose of ease and conveniencein explanation. In other words, differences between the presentembodiment and the embodiment of FIGS. 3 to 11H will be mainly describedhereinafter.

Referring to FIGS. 15 and 16A to 16D, a substrate 100 having a thirdregion RG3 and a fourth region RG4 may be provided. The third region RG3and the fourth region RG4 may be a logic cell region or a peripheralcircuit region. The substrate 100 may be patterned to form activepatterns AP. The formation of the active patterns AP may include formingmask patterns MA on the substrate 100, and anisotropically etching thesubstrate 100 using the mask patterns MA as etch masks. First trenchesTR1 may be formed between the active patterns AP.

Referring to FIGS. 15 and 17A to 17D, a mold layer MO may be formed onthe third region RG3. The mold layer MO may completely cover the activepatterns AP on the third region RG3. The mold layer MO may expose thefourth region RG4.

Liner layers LIN may be formed to cover exposed sidewalls of the activepatterns AP on the fourth region RG4. In more detail, a liner layer LINmay be conformally formed on the substrate 100, and the conformal linerlayer LIN may be anisotropically etched. Thus, the liner layers LINhaving spacer shapes may be formed on the sidewalls of the activepatterns AP of the fourth region RG4. On the other hand, the thirdregion RG3 may be protected by the mold layer MO, and thus the linerlayers LIN may not be formed on the active patterns AP of the thirdregion RG3.

Referring to FIGS. 15 and 18A to 18D, the substrate 100 may be etchedusing the mold layer MO, the mask patterns MA and the liner layers LINas etch masks to form second trenches TR2 in the substrate 100 of thefourth region RG4. Due to the mold layer MO, the substrate 100 of thethird region RG3 may not be etched during the etching process. Thesecond trenches TR2 of the fourth region RG4 may be deeper than thefirst trenches TR1 of the third region RG3. Meanwhile, each of theactive patterns AP on the fourth region RG4 may include a first portionPA1 and a second portion PA2 on the first portion PA1.

Since the liner layers LIN are used as the etch masks in the etchingprocess, a sidewall of the first portion PA1 of the active pattern AP ofthe fourth region RG4 may be aligned with an outer sidewall of the linerlayer LIN. A sidewall of the active pattern AP of the fourth region RG4may have a stepped profile at a boundary between the first portion PA1and the second portion PA2.

Referring to FIGS. 15 and 19A to 19D, the mold layer MO may be removed.A device isolation layer ST may be formed in the first and secondtrenches TR1 and TR2. In more detail, an insulating layer may be formedon the substrate 100 to completely cover the active patterns AP. Theinsulating layer may be planarized until top surfaces of the activepatterns AP are exposed. At this time, the mask patterns MA may beremoved. Thereafter, the planarized insulating layer may be recessed toexpose upper portions of the active patterns AP. The recessed insulatinglayer may correspond to the device isolation layer ST. The liner layersLIN may also be recessed when the insulating layer is recessed.

Referring again to FIGS. 13 and 14A to 14F, as described above withreference to FIGS. 6 to 11H, sacrificial patterns may be formed,source/drain regions SD may be formed at both sides of each of thesacrificial patterns, and the sacrificial patterns may be replaced withgate electrodes GE.

In the semiconductor device according to some embodiments of theinventive concepts, the liner layer may be provided on a region in whicha distance between the active patterns is relatively wide. The linerlayer may protect the source/drain of the NMOSFET. In addition, theliner layer may prevent the active patterns from leaning and may providethe tensile stress to the channel of the NMOSFET.

While the inventive concepts have been described with reference toexample embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirits and scopes of the inventive concepts. Therefore, itshould be understood that the above embodiments are not limiting, butillustrative. Thus, the scopes of the inventive concepts are to bedetermined by the broadest permissible interpretation of the followingclaims and their equivalents, and shall not be restricted or limited bythe foregoing description.

What is claimed is:
 1. A semiconductor device comprising: first activepatterns and second active patterns on a substrate; a first source/drainregion on the first active patterns; a second source/drain region on thesecond active patterns; a device isolation layer filling a first trenchbetween adjacent ones of the first active patterns and a second trenchbetween adjacent ones of the second active patterns; a liner layer onthe device isolation layer between the adjacent ones of the secondactive patterns; and an etch stop layer on the liner layer, wherein thedevice isolation layer between the adjacent ones of the first activepatterns has a recess therein under the first source/drain region, andwherein a bottom surface of the liner layer between the adjacent ones ofthe second active patterns is higher than the recess.
 2. Thesemiconductor device of claim 1, wherein a first air gap is definedbetween the first source/drain region and the recess and wherein asecond air gap is defined between the second source/drain region and theliner layer.
 3. The semiconductor device of claim 1, wherein the linerlayer covers sidewalls of upper portions of the second active patternsand a top surface of the device isolation layer between the secondactive patterns.
 4. The semiconductor device of claim 1, furthercomprising: first channel regions in upper portions of the first activepatterns; second channel regions in upper portions of the second activepatterns; a first gate electrode on the first channel regions; a secondgate electrode on the second channel regions; and an insulating patterndisposed between the second gate electrode and the liner layer.
 5. Thesemiconductor device of claim 1, wherein the liner layer comprises asilicon nitride layer.
 6. The semiconductor device of claim 1, whereinthe first active patterns have upper portions vertically protruding fromthe device isolation layer between the first active patterns, and thesecond active patterns have upper portions vertically protruding fromthe device isolation layer between the second active patterns.
 7. Asemiconductor device comprising: a substrate having a first region and asecond region; first active patterns on the first region; second activepatterns on the second region; a device isolation layer defining thefirst and second active patterns on the first and second regions; aresidual spacer layer on the device isolation layer between adjacentones of the first active patterns; and a liner layer on the deviceisolation layer between adjacent ones of the second active patterns,wherein a pitch between the second active patterns is greater than apitch between the first active patterns, and wherein a bottom surface ofthe residual spacer layer is higher than a bottom surface of the linerlayer.
 8. The semiconductor device of claim 7, further comprising: afirst gate electrode crossing the first active patterns; a second gateelectrode crossing the second active patterns; and gate spacers on bothsidewalls of each of the first and second gate electrodes, wherein theresidual spacer layer includes a same material as the gate spacers. 9.The semiconductor device of claim 8, wherein a width of the first gateelectrode is smaller than a width of the second gate electrode.
 10. Thesemiconductor device of claim 7, wherein the liner layer coverssidewalls of upper portions of the adjacent ones of the second activepatterns and a top surface of the device isolation layer between theadjacent ones of the second active patterns.
 11. The semiconductordevice of claim 7, further comprising: a first source/drain region onthe first active patterns; and a second source/drain region on thesecond active patterns, wherein a first air gap is defined between thefirst source/drain region and the residual spacer layer, and wherein asecond air gap is defined between the second source/drain region and theliner layer.
 12. The semiconductor device of claim 11, wherein the firstsource/drain region and the second source/drain region have a sameconductivity type or different conductivity types.
 13. The semiconductordevice of claim 7, wherein a width of each of the first active patternsis substantially equal to a width of each of the second active patterns.14. The semiconductor device of claim 7, wherein the liner layercomprises first liner layer and wherein the semiconductor device furthercomprises: a second liner layer disposed between the residual spacerlayer and the device isolation layer disposed between the adjacent onesof the first active patterns, wherein a bottom surface of the secondliner layer is higher than the bottom surface of the first liner layer.15. The semiconductor device of claim 7, wherein the first activepatterns have upper portions vertically protruding from the deviceisolation layer between the first active patterns and the second activepatterns have upper portions vertically protruding from the deviceisolation layer between the second active patterns.
 16. A semiconductordevice comprising: first active patterns and second active patterns on asubstrate; a first source/drain region on the first active patterns; asecond source/drain region on the second active patterns; a deviceisolation layer filling a first trench between adjacent ones of thefirst active patterns and a second trench between adjacent ones of thesecond active patterns; and a protective insulating layer covering thesecond source/drain region and an upper sidewall of at least one of thesecond active patterns, wherein a thickness of the protective insulatinglayer on the upper sidewall of the at least one of the second activepatterns is greater than a thickness of the protective insulating layeron the second source/drain region, wherein a first air gap is definedbetween the first source/drain region and the device isolation layer,and wherein a second air gap is defined between the second source/drainregion and the device isolation layer.
 17. The semiconductor device ofclaim 16, wherein the protective insulating layer includes: a linerlayer extending from the upper sidewall of the at least one of thesecond active patterns onto a top surface of the device isolation layer;and an etch stop layer covering the second source/drain region.
 18. Thesemiconductor device of claim 17, wherein the etch stop layer furthercovers the first source/drain region.
 19. The semiconductor device ofclaim 17, further comprising: a gate electrode crossing the secondactive patterns; and an insulating pattern disposed between the gateelectrode and the liner layer.